Expanding the Use of TAVR for Aortic Stenosis

By Helen Garey

For people living with the shortness of breath, fatigue, and other symptoms caused by aortic stenosis, a long-established procedure is now the preferred treatment for most patients over open-heart surgery. Transcatheter aortic valve replacement, or TAVR, was developed over two decades ago to help patients living with severe aortic stenosis, a common heart valve problem that affects around 5% of people over age 75. TAVR is a minimally invasive approach that involves inserting a catheter through a blood vessel, usually in the groin, and threading it up to the heart to deliver a new valve. While TAVR was initially used to treat patients who were too sick for open-heart surgery, recent clinical trials have shown that it is a safe and effective therapy for a wider range of patients.

Martin B. Leon, MD, professor of medicine and director of the Cardiovascular Data Science Center for the Division of Cardiology at Columbia, pioneered the procedure. He explains how TAVR has become a mainstream treatment option for millions of people worldwide.

How did the idea for TAVR get started?

Severe narrowing of the aortic valve can cause debilitating symptoms such as shortness of breath, chest pain, lightheadedness, and profound fatigue, making everyday activities difficult. However, unlike conditions such as arrhythmias or hypertension, there is no medication to treat aortic stenosis. Half of patients with aortic stenosis die in the first one to two years after diagnosis; that’s a survival rate worse than most cancers.

For over 60 years, replacing the aortic valve with open-heart surgery was the standard therapy for aortic stenosis. But there was a growing number of older patients for whom open-heart surgery is too risky. At the same time, physicians were getting better at using transcatheter therapies, which deliver treatments to the heart via a catheter inserted into the groin rather than opening the chest. So, we decided to develop a transcatheter therapy for patients with aortic stenosis.

Some people called this concept of replacing the aortic valve through a catheter radical because it was a new way of replacing a whole heart structure. But the first case—performed in 2002 in France on a patient in his 50s who was too ill for surgery—was very successful. The first case at Columbia was performed three years later. We then needed to conduct large randomized clinical trials to show that TAVR could be an effective alternative to surgery.

What were the results of the clinical trials?

The first major randomized clinical trials began in 2007. Over 10,000 patients worldwide were included in five trials, starting with the sickest patients who could not have surgery.

The next set of trials studied patients with severe aortic stenosis who were able to have surgery and compared outcomes of TAVR versus open-heart surgery to replace the valve. After one year, we found that patients who had TAVR did better—meaning they had lower rates of stroke, rehospitalization, or death—than those who had surgery. Five years after treatment, TAVR was just as safe and long-lasting as surgical valve replacement. Based on these results, TAVR became the preferred therapy for patients.

Has TAVR advanced over the years?

The first major randomized clinical trials in 2007 used first-generation devices that were much larger than the ones used today, and we still saw a dramatic reduction in deaths after TAVR.

Since then, the devices have improved significantly. Current devices are smaller and more durable. We also have better imaging and other techniques that have refined our ability to diagnose, monitor, and treat patients.

What’s next for TAVR?

Based on improvements to the device and our encouraging trial results in Martin B. Leon patients with low surgical risk, we began to consider using TAVR as an upstream therapy for patients with severe aortic stenosis who do not have symptoms yet. Many of these patients are in their 70s and 80s, and getting them to report symptoms can be more difficult. Typically, these patients are monitored every six months, but sometimes they miss their appointments. By the time patients have symptoms, many already have permanent heart damage.

In the latest randomized trial, published in NEJM last year, we studied these older, asymptomatic patients and compared the outcomes of those who had TAVR with those only receiving clinical surveillance (meaning we actively monitored the patients). We found that patients who had undergone TAVR had significantly lower incidences of death, stroke, and repeat hospitalizations for heart issues two years later compared to patients who had clinical surveillance. The procedure was also remarkably safe, with zero mortality for 30 days after and low complication rates. In addition, after two years, nearly all the patients who were being monitored developed symptoms and went on to have the TAVR procedure.

What did you learn from this trial?

This trial tells us we should consider treating patients as soon as they have severe aortic stenosis, even if they do not report symptoms. We have also learned that patients can rapidly go from being asymptomatic to having symptoms, so waiting does not buy much time. Furthermore, by the time patients develop symptoms, about 40% have advanced heart failure, and they are experiencing fainting spells and rapid arrhythmias.

For comparison, early-stage lung cancer is often asymptomatic. But if you saw the cancer on a chest X-ray, you would not wait for symptoms to start treatment.

What can patients undergoing TAVR expect?

The procedure takes less than an hour while the patient is awake. Most patients leave the hospital the next day. We have seen dramatic improvements in the way patients feel even a month after the procedure.

What’s the takeaway for patients and physicians?

Currently, TAVR is used to treat over 100,000 patients a year by physicians at over 900 medical centers, many of whom were trained by Columbia physicians.

Later this year, the FDA will consider expanding the indication for TAVR to include asymptomatic patients with severe aortic stenosis. The approval could double the pool of patients who could be candidates for TAVR.

Starting at age 65, patients should be monitored with an echocardiogram for signs of aortic stenosis, and those with mild stenosis should be sent to a heart valve center to be evaluated more extensively.

Patients who have asymptomatic stenosis should see a cardiologist who understands valve disease every few months to determine the earliest time they can have treatment. In the meantime, we’re continually working to improve diagnosis and clinical surveillance.

Vivian Ng, MD, assistant professor of medicine and director of Clinical Services in the Structural Heart and Valve Center at Columbia, provided additional information for this article.